Neuroendocrine cancer of the lung includes small cell lung cancer (SCLC), large cell neuroendocrine carcinoma (LCNEC), and typical and atypical carcinoid tumors.[1] LCNEC and SCLC are characterized by a more aggressive clinical course and pathologically higher mitotic rates, immunoreactivity to neuroendocrine markers, and high Ki-67 scores.[1] Unlike other neuroendocrine cancer subtypes, SCLC is fairly common. In conclusion, we report the first case of high-grade neuroendocrine carcinoma of the lung with inactivating I CDK12 i SNV mutation that showed an ongoing, durable, partial treatment response to olaparib and paclitaxel combination therapy for 5 months. DISCUSSION In summary, this refractory, metastatic, I CDK12 i -mutated high-grade neuroendocrine cancer of the lung showed a durable treatment response to olaparib and paclitaxel combination therapy for 5 months. [Extracted from the article]